1. Field of the Invention
The present invention relates to vehicle antennas. More specifically, the present invention provides a vehicle antenna formed as part of the support structure of the vehicle's roof.
2. Description of the Related Art
Numerous antenna structures have been proposed for use with vehicles. However, the present inventors are not aware of any presently existing antennas formed as part of the support structure of a vehicle's roof.
An example of a presently available antenna is disclosed within the U.S. Pat. No. 3,289,962, issued to D. W. Young on Aug. 13, 1974. This patent discloses an antenna structured for mounting within the front edge of an airplane wing. The waveguide antenna is made from an aluminum extrusion having a T-shaped cross section and a hollow interior. One side includes a series of holes arranged in a pair of groups disposed alternately above and below the center line of the sidewall. Upper and lower longitudinal flanges extend forward from the upper and lower edges of the sidewall defining the holes. A ridge member is slidably mounted in the stem of the T-shaped extrusion, and is operatively connected to a reciprocating yoke member having a rotary shaft with an eccentric disk having an oblong opening. Dielectric strips are mounted in front of the side having the holes, and are covered themselves with foam. The entire structure is then covered with fiberglass. The antenna itself does not form a portion of the structure of the aircraft.
U.S. Pat. No. 4,200,870, issued to C. Gabbitas on Apr. 29, 1980, discloses a microwave transmitter/receiver unit having a hollow waveguide assembly that is open at one end. The assembly is divided longitudinally into a transmitting waveguide and a receiving waveguide. A transmitting diode is mounted within the transmitting waveguide. A pair of receiving diodes mounted a number of quarter guide wavelengths apart within the receiving waveguide.
U.S. Pat. No. 5,896,107, issued to T. D. Huynh on Apr. 20, 1999 discloses an antenna system. The antenna includes a ground plate disposed between a back plate and a patch plate. The patch plate includes conductive patches spaced lengthwise along the patch plate, with each conductive patch having a length of approximately one-half wavelength. The ground plate has a dielectric body with a conductive slot layer facing the patch plate. A plurality of slots are etched into the conductive coating. Each pair of slots corresponds to one of the patches on the patch plate, and forms an X shape. The side of the ground plate facing the back plate includes a multi-strip feed network layer having a pair of feed lines and a plurality of feed probes which are capacitively coupled to the conductive patches through the slots within the slot layer. A first set of feed probes includes a plurality of pairs of feed probe members that are connected to the conductive patches through one set of polarization slide elements. The second set of feed probes include a plurality of single feed probes that are connected to the conductive patches through the other of the slide elements. Coupling through the first polarization slots causes polarization in a first direction, and coupling through the second polarization slots causes polarization in a second direction perpendicular to the first direction.
U.S. Pat. No. 6,669,267, issued to M. R. Lynam, et al. on Dec. 30, 2003, discloses an exterior accessory module for a vehicle door. The module may include an antenna for passive entry devices, a microwave antenna, GPS antenna or radio frequency antenna. While the antenna is contained within the module, it does not form a part of the structure of the vehicle, and is also located relatively low on the vehicle. The reception of an antenna is maximized by placing the antenna as high as possible on the vehicle.
None of the above antennas forms a structural component of the vehicle in which it is incorporated. The combination of an antenna and a structural component of a vehicle results in a more streamlined vehicle design. Combining an antenna with the structure of a vehicle would also result in a more durable antenna. Accordingly, there is a need for an antenna that is also a structural component of the vehicle in which it is used.